1. Field of the Invention
The present invention relates to sampling and measuring. More specifically, it relates to sampling precise volumes of powder blends, especially pharmaceutical powder blends. Even more specifically, it relates to a sampling device or sampling thief, wherein sampling dies having cavities of varying, specific volumes can be placed within receiving areas in sampling rods. The rods and the dies disposed therein are then placed within an outer tube that includes apertures that are rotatably alignable with the receiving areas and, thus, the cavities in the dies. The entire device then can be inserted into a powder blend and the inner sampling rods are rotated such that the outer apertures are aligned with the cavities in the dies, allowing predetermined volumes of the powder to be collected. The inner rods are then rotated such that the apertures in the outer tube are no longer aligned with the cavities, and the device is withdrawn from the powder, the outer tube removed, and the dies withdrawn from the sampling rods, and the powder samples removed for testing purposes.
2. Description of the Prior Art
In the manufacturing of solid dosage form pharmaceuticals, one of the steps is blending different active and inactive ingredients in a blender. Such powder blends are routinely sampled for testing of content uniformity. A proper sampling technique requires unit-dose sampling from different areas of the blender, for example, top, middle and bottom of a blender. Unit-dose sampling is defined herein as taking just enough of an amount of the powder blend to provide one dose of the active ingredient. This proves to be a difficult task in the pharmaceutical industry because of the large number of products with varying doses and bulk densities and different sized blenders used. This requires several sampling thieves that are currently available, increasing the cost to the manufacturer. The present invention overcomes this drawback by providing: (1) a sampling device where a variety of different dies , each one having a cavity of precise volume, are interchangeable within the apparatus; (2) as an alternative, an adjustable volume die; and (3) a sampling rod structure in sections, providing the flexibility of sampling rod length.
A number of patents have been issued that address sampling of various materials. These will be discussed in order of their perceived relevance to the claimed invention.
In the German patent document DD 285,639 A5 published on Dec. 19, 1990 to Rolf Hoffman et al. there is disclosed a sampling device where the chamber is rotatable to receive and discharge a sample.
In USSR patent 204,682 issued on Jul. 28, 1967 to G. K. Kushchanov there is disclosed a sampler that discloses a pipe having inclined shelves. The pipe is disposed within a cylindrical body having ports and gates to allow samples to be collected as the device is axially rotated.
In U.S. Pat. No. 2,968,184 issued on Jan. 17, 1961 to James R. Archer et al. we see a sampling tube having a receiving member and a cover member. The cover member is slidable relative to the receiving member which is in the form of a tube and has holes cut therein. Thus, the device can be inserted into a material to be sampled and the cover is slid back to allow the material to enter the holes in the receiving member. The cover is then slid back into a closed position and the device is withdrawn.
In U.S. Pat. No. 4,442,721 issued on Apr. 17, 1984 to Laura G. Singer there is disclosed a moisture and consistency soil sampler. This comprises an elongate member with en insertable end, a handle end, and a plurality of generally transverse collecting means disposed proximate the insertable end that define soil collecting pockets.
The last patent to be discussed in detail is U.S. Pat. No. 4,518,076 issued on May 21, 1985 to Armin Feisel et al. In this document there is shown a workpiece pallet tray with plastic insert holders. Inserts are provided that snap fit into the holding areas in the tray.
Other patents that disclose apparatus for sampling various materials are listed below.
______________________________________ U.S. Pat. No. INVENTOR DATE OF ISSUE ______________________________________ 3,575,055 Thornton, Jr, April 13, 1971 3,595,088 Meunier July 27, 1971 3,875,803 Clewlow April 8, 1975 3,943,771 Handa et al. March 16, 1976 4,022,065 Ramin et al. May 10, 1977 4,055,088 Dias October 25, 1977 4,283,946 Bowser et al. August 18, 1981 4,361,052 Nicol et al. November 30, 1982 4,580,577 O'Brien et al. April 8, 1986 4,641,540 Ellis February 10, 1987 4,951,511 Perron et al. August 28, 1990 ______________________________________
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.